Question

Tính các giới hạn sau:

a) \(\lim\limits\dfrac{2n^2+5}{-3n^2-3}\)

b) \(lim\left(-5n^3-2n^2+5n-6\right)\)

 

Answer 1

`a)lim[2n^2+5]/[-3n^2-3]`

`=lim[2+5/[n^2]]/[-3-3/[n^2]]`

`=2/[-3]=-2/3`

`b)lim(-5n^3-2n^2+5n-6)`

`=lim n^3(-5-2/n+5/[n^2]-6/[n^3])`

Vì `{:(lim n^3=+oo),(lim (-5-2/n+5/[n^2]-6/[n^3])=-5):}}=>lim n^3(-5-2/n+5/[n^2]-6/[n^3])=-oo`